Std touring car is 186-190mm but if you want wheels to tuck inside you might want to start with a "mini" chassis to start modding from. Mini track starts from about 165mm, add your +10 wheels both sides & you're up to 185 etc etc

Wheelbase is next issue... if you've stolen a toy shell you'll probably not be covering 260mm std wheelbase.

Haha how about a crawler? :) some ppl have drifted a Tamiya CC01 chassis...